In The Presence of the Kingdom, Jacques Ellul says that "the Christian should neither withdraw from the world, nor be lost in the midst of the world. Instead, the Christian should bring the reign of God and the world into collision."
Contrary to advocating withdrawal from the world or urging a lifeboat, Ellul challenges us to embrace and preserve the world. God alone will effect our separation in hi own time. This resolute engagement requires a dialectical and antagonistic style of life which remain very much in the world even as it rejects worldliness. To be in the world also requires us to understand it in both its material and spiritual aspects, a task Ellul has undertaken in his sociological and theological works and which he challenges us to better. By rejecting the twin perils of spiritualization (which neglect material realities) and capitulation (which simply adopts one of the world's many different options that appears to harmonize with Christianity), the Christian plays a truly creative role and gives meaning and direction to history, which otherwise has no logic or certitude.
Authentic Christian existence trusts in the power of the Holy Spirit to give our "presence" a revolution and explosive force in history.